# Matrix-Vector Product (Symmetric) (G Dataflow)

Calculates the product of a symmetric matrix and a vector.

## A

Symmetric matrix.

A must have at least N rows and N columns, where N is the number of elements in x.

This node multiplies the first N rows and first N columns of the upper or lower triangular component of A by x, depending on the value you wire to matrix A type.

## x

N-element vector.

## y

Input vector.

y must have at least N elements, where N equals the number of elements in x. If y is an empty vector, this node initializes y to be an N-element vector with all elements set to 0.

## matrix A type

Triangular component of A that this node uses for the calculation.

Name Value Description
Lower Triangular 2 Uses the lower triangular component of A for the calculation.
Upper Triangular 3 Uses the upper triangular component of A for the calculation.

Default: Upper Triangular

## error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

## alpha

Scalar that scales A * x.

Default: 1

## beta

Scalar that scales y.

Default: 1

## dsymv

Vector of the same size as y.

For the first N elements, dsymv returns the result of alpha * A * x + beta * y. For any remaining elements, dsymv returns the value of the element in y with the same index.

## error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application